1. Field of the Invention
The invention relates to clamping and/or transporting of paper, particularly stacks of paper in which, after a printing or copying operation, the stack of paper is to be transported to a treatment station, such as stapling or binding device. The invention is particularly desirable in the context of a copying or printing machine, in which, after copying, a stack of sheets are received in a bin, with the stack then clamped and transported to a binding device in the clamped condition.
2. Discussion of Background
Often, a copying machine or printing apparatus will include a suitable device for binding or attaching a stack of sheets to one another after completion of the copying or printing process. For example, a stapling device or a perforating/binding device can be provided, with a clamp holding the stack of sheets during the binding operation.
FIG. 7 shows an example of a paper clamping arrangement as disclosed in Japanese Laid-Open Patent Publication No. 2-23154/1990. The clamping apparatus includes a fixed support portion 100, with a clamping assembly designated generally at 110. The clamping assembly 110 can be reciprocated forwardly and backwardly in the direction indicated by arrows and A and B. Mounted upon the support 100 is a motor 101, a pair of gears 102, 103 for reducing the rotational speed of the motor 101 and changing the direction of rotation, as well as a screw or threaded shaft 105 for transmitting the rotation of the motor 101 to the clamping assembly 110 via an intermediate movable bar 104 having a threaded hole therein. As the motor rotates, the shaft 105 causes the bar 104 to translate, thereby causing translation of the clamping assembly 110 connected thereto.
As also shown in FIG. 7, the clamping assembly 110 includes a pair of clamp levers 111, 112 for clamping a stack of sheets which are discharged onto the bin 120 in the direction indicated by arrow C. The upper clamp lever 111 is mounted upon the assembly 110 such that it is movable to effect a clamping operation, while the lower clamp lever 112 is fixed. Further, the upper clamp lever 111 is resiliently biased into a release position via spring 113, with the clamp 111 driven to effect clamping by a solenoid 114. Thus, during actuation of the solenoid, the clamp 111 is moved downwardly, and upon release of the solenoid, the spring 113 causes a release of the clamp.
In operation of the clamping arrangement shown in FIG. 7, the motor 101 rotates in order to rotate the threaded shaft 105, thus moving the bar 104 and clamping assembly 110 to a forward grasping position. Power is then supplied to the solenoid 114, and a stack of sheets located on the bin 120 is clamped by the clamp levers 111, 112. Thereafter, the motor 101 rotates in a reverse direction to retract the clamping assembly to a treatment position at which a stapling or binding operation takes place. The binding apparatus (not shown in FIG. 7) is disposed at the side of the clamp apparatus, and performs the binding operation when the clamping assembly is in the retracted and clamped condition. Thereafter, the motor 101 rotates to advance the clamping assembly, with the solenoid 114 then released, thereby returning the bound stack of sheets to the bin. The clamping assembly 110 then retreats to a waiting position for the next binding operation.
Although only a single bin 120 is shown in FIG. 7, typically, plural bins are arranged which are parallel to one another, and which are stacked vertically. The clamping apparatus and the subsequent treatment unit (e.g., a binding apparatus) are movable up and down to service the plural bins.
In the arrangement as shown in FIG. 7, a cumbersome design is required since the mounting of the binding apparatus must accommodate for the clamping assembly. The arrangement becomes more inconvenient when it is desirable to bind a stack of sheets at more than one location, since the binding apparatus is required to move from a first binding location to a second binding location, and such movement can be obstructed by the clamping assembly. Accordingly, the clamping arrangement as shown in FIG. 7 severely limits the flexibility of subsequent treatment operations, such as binding operations, or at least, greatly complicates such binding operations. Moreover, the clamping assembly as shown in FIG. 7 is generally only suitable for carrying the stack of sheets in forward and backward reciprocating movement, thereby limiting the options available for placement of the binding apparatus. For example, if the FIG. 7 arrangement were utilized to transport a stack of sheets in a direction perpendicular to arrows A-B, the sheets can become skewed, resulting in an unacceptable bound stack.
Accordingly, an improved clamping and transporting arrangement is needed which can conveniently and reliably transport a stack of sheets from a first location, such as in a bin, to a second location at which a binding operation can be easily effected. Such an arrangement should be capable of securely clamping and moving a stack of sheets, without allowing the sheets to move relative to one another or become jumbled, while being able to present the stack of sheets to a variety of subsequent treatment apparatus, such as a binding device which can bind the stack of sheets at one or more locations. In addition, the clamping and transport assembly should be relatively simple, without requiring numerous driving arrangements and/or control systems to synchronize the various movements required for moving the clamping assembly, effecting a clamping operation, and transporting a clamped stack of sheets to a binding device. Further, the clamping assembly should be capable of sustaining moment forces as the stack of sheets are transported, without allowing any of the sheets of the stack to become skewed which would result in an unsatisfactory binding operation.